Thrombin-Preconditioned Human WJ-MSCs Protocol

After obtaining informed consent from pregnant mothers, we isolated, expand, and preconditioned human WJ-derived MSCs with thrombin (2 U/mL; Sigma Aldrich, Steinheim, Germany) at Good Manufacturing Practice (GMP) facility of the Samsung Stem Cells and Regenerative Medicine Institute following the guidelines for GMP, as described previously [13 (link)]. Briefly, the MSCs characteristics were confirmed using flow-cytometric analysis for cell surface markers (CD73, CD90, CD105, CD166, CD14, CD11b, HLA-DR (MHCII), CD34, CD45, and CD19) and in vitro differentiation assays for osteogenesis, adipogenesis, and chondrogenesis as described [24 (link)]. After reaching 90% confluence, we preconditioned WJ-derived MSCs with thrombin in a culture medium (α-MEM; Gibco, Life Technologies, Carlsbad, CA, USA) for 3 h. Control naïve MSCs were prepared in the same manner except for thrombin treatment.